Ignition apparatus



Dec. 30, 1947. s. K. SMART ET AL IGNITION APPARATUS Filed A ril 18., 1946 5 Sheets-$heet 1 INVENTOR M Aural BY 4 6M 9 ATTOR YS v Dec. 30, 1947.

S. K. SMART ET AL IGNITION APPARATUS Filed April 18, 1946 5 Sheets-Sheet 2 5 Sheets-Sheet 3 IGNITION APPARATUS Filed April 18, 1946 .5 K. SMART ET AL Dec. 30, 1947.

Dec. 30, 1947.

S. K. SMART ET AL IGNITION APPARATUS 5 Sheet-Sheet 5 Filed April 18, 1946 INVENTOR a/vz'r ff. J-Mlir mm A4 LE/f Lflnommzz 7 7 AT i O EYS Patented Dec. 30, 1947 UNITED STA-TEST PATENTS orsrioe IGNITION' APPARATUS Sidney 1K. Smart,Agawam, and Allen L. Brownlee,

West Springfield, Mass, assignors; to Wioo- Electric Company, West Springfield, Mass.,.,a, corporation of Massachusetts Application April 18,- 1946,:SeriaLNoa 663g098: 3

3 Claims. (Cl. 320 -1) This invention relatesto nition apparatus for use in ignition systems for improvements in 'iginternal combustion engines.-,and,- more partic-- ularly, ignition systems of the-low-tension, high,-

frequencytype, intwhich theignition sparkisproduced bya dischargefromza capacitor.

One exampleof an ignition system of thetype referred to,,is disclosedin. the copending application, for U. .8. Letters Patent .of-Kenneth A.

Harmon and Allen L. Brow-n1ee,.filed December- 7, 1944, under Serial No; 567,092,- and'assigned to thewassignee of-the present application. the. system of: theuprior application, an enginedriven alternatingrcurrent generator is utilized to chargea capacitor through a full-wave rectifier andthe discharges from-the capacitor are. controlled andutimedbya distributor driven by, At

andin. timed. relation with, the generator. proper intervals, the distributor completes-a discharge. circuit. from the capacitor and, the

charge, which. was .built upbythe generator and maintainedatitstpeak bythe-rectifier, is

discharged at low. tension through the primary of a sparkplugtransformer; A high voltage is induced in the secondary of the transformer and.

a discharge occurs across. thev gap of the plug at a frequency inethe neighb'orhoodl of one megacycle.

This invention has. iorone ofits objectsto provide an improvedapparatus .for use. in an igr nition system of thetypedisclosed in said prior application.

Theinvention has for a further object the provision within a single housing, and as one unit,

all the apparatus required for ansignition system of the'kind described. except for those parts which are necessarily located at the engine such as the spark plug andspark-plug transformers...

and the necessary distribution wires.

The invention hasfor another object the provision. of ignition apparatus, suchlas described, in a single unit, whichis made upof twogroups,

one comprising, all. the parts, of the. electrical gen.- erator and the othercomprising all those parts needed to adapt thelgenerator, for use Cinan. ig-.-

nition system of the class-.des'cribedsuch ,forlexample as-the. capaciton. rectifier .and.timing-disj-..

tributing means- The'invention has for a further object'the proe vision of, a simple. anda compact arrangement of parts withinasingle casing, whichis adapted for attachment to the housing of a generator .of

suitable characteristics, whereby'an ignition system' of thelkinddisclosedin the .prior application, can be'produced by attaching the casing to the generators and by applyingl distribution wires to connect terminals on-wthe --casing to the several spark plugatransformers, located, at the engine cylinders.

The invention has fomother: objects improve ments.. in the arrangementand .mounting of parts, such as the-recti fier capacitor and timing.-.

distributing means The inventionwill be described :with reference to' the accompanying drawings, in which,

Fig. 1 is an exterior-end elevationaliview of an ignition. apparatusembodying the invention;

Fig. 2 is a sectional elevational view taken ,on theline. 22 of. Fig. .1;

Figs. 3..and .4 are crosssectionalviews taken on p the lines. 3,TI3. and, 4. 4," respectively, of, Fig. 2;

Fig..,5.is an end. .elev'ational view,. showing the insideeof the cover of, theihousinglof the apparatusand; the parts mounted thereon;

Figs. 6. and. l are sectional elevational views taken. on, the-lines. .6'.-6- andv 1-1, respectively, of .Fig'. 5.;

Fig.8 is a fragmentary sectional .plan view takenon the line 8--Bof Fig. 6;

Fig.' 9 is a fragmentary cross sectional view taken onthei line .9-9 of. Fi 6;

Fig". tlO'is afra'gmentarycross sectionalviewi" takenontheline lll- -lfi of Fig.2;

Fig. llfisa fragmentary exterior side-eleva-' tional View of, the cover:

Fig; ,12"is a fragmentarysectional view taken" Fig. 133s a view showingpnetof the distributor contacts and.

Fig. 14 .is a diagrammatical"view-showing the electrical connections'of the apparatus.

Refer'ringto these drawings and. first to 'Fig. 2 thereof; the housing for the apparatus includes a hollow,die-cast member I of non-magnetic metal; whichha'sian'end'wal1'2 with an" opening therethroughlargei'enough to :permit passage 'of thej;rotor,"and"a peripheral'wa'll 3. The housing also includes a die-cast cover 4 of similar materiaLcwhich has, an end wall 5 anda periph= 'eral" wall 6; Theperipheral wallst andB are heldtoget-her; witha gasket 1 clamped 'therebetweenyby a plurality Of screws 8 (Fi gs; 1 and-4') which pass through the cover and are threaded" into wall =32 The wallt preferablyhas a plural-- ityJ-of spaced fl'anges fl (-Fig'sfa) which engage in i sidertheiwalli EeCFigs. 2 an'd:14')1 to maintain: the:

peripheral .walls 3t. andsfi ;in-talignment.:

The housing .may :be :mounted; either 'hOIiZOIlF tally: or everti-cally; .,-as, desired, and willhave inounting flanges, which are appropriate for the U style of mounting desired. The particular housing shown is adapted to be mounted horizontally and to be secured to the crankcase a (Fig. 2) of an internal combustion engine. For this purpose, the end wall 2 has an annular pilot flange ill to closely fit a cylindrical opening b in such crankcase and a mounting flange ll adapted to be suitably secured to a wall of the crankcase, as for example, by a cap screw 0, passing through a slot 11 in an ear e on the crankcase a and threaded into the hole l2 in flange II, and by a bolt f passing through a hole in another ear 9 on the crankcase a and through a slot 13 (Fig. 2) in the flange.

The stator of the magneto (Figs. 2 and 3) includes a laminated core I4 of magnetic material, on which is mounted a coil 15, and suitable pole pieces l6, each of laminated magnetic material and each having parallel extensions [1 (Fig. 3), the outer ends of which are engaged one with each of the ends of the core 14. The number, shape, size and location of these pole pieces will Vary according to the particular use for which the magneto is designed. These pole pieces are permanently fixed to a non-magnetic frame member l8 by rivets [9 (see also Fig. 4). This unit, comprising the frame [8 and pole pieces I6, is clamped against a seat 20 (Fig. 2) on the end wall 2 of the housing by means of a plurality (four as shown in Fig. 4) of irremovable screws 2|. The heads of these screws are so formed that they may be turned inwardly but not outwardly, Thus, this unit is permanently fastened in the housing.

The member [8 also has therein a ball bearin 22 (Fig. 2) for supporting one end of the shaft 23 of the magnetic rotor. The other end of such shaft is supported by a ball bearing 24 mounted in a cage or support 25, seated in a counterbore in the cylindrical opening in the end wall 2 of housing member I. After the above described unit has been clamped to its seat 20 in the housing member I, the bore for the bearing 22, the arcuate surfaces 26 of the several pole pieces, the counterbore for cage 25 and its shoulder, and another and larger counterbore for a bearing-retaining disk 21 and its gasket 28, are finished at one time. .Thus, it is insured that all the surfaces described are in true coaxial relation. After these machining operations have been performed, the magnetic rotor is inserted in place with its shaft 23 engaged in bearing 22. The bearing 24 in its cage 25 is then placed on the shaft 23 and then the support or cage 25, the periphery of which has previously been machined to closely fit the counterbore in housing member I and to lie in true coaxial relation with the bearing 24, is placed in such counterbore. Then gasket 28 and disk 2'! are put in place and held there by a plurality of screws 29 and Washers 30, the latter partially overlapping disk 21. The disk 2! thus serves to retain the bearing support 25 seated against the shoulder in its counterbore.

The magnetic rotor comprises a cylindrical permanent magnet 3| (Figs. 2 and 3) having a central, axially-disposed hexagonal opening therethrough to receive a knurled portion 32 (Fig. 2) of shaft 23. Pole shoes 33 (Fig. 3) of laminated magnetic material have inner surfaces curved to fit the periphery of the magnet 3|. These shoes are riveted together, as at 34, and spot welded to the magnet, Then, the magnet 3|, shoes 33' and shaft 23 are placed in a suitable 4 die and non-magnetic metal 35 is cast therein to fill the space between the knurled part 32 of the shaft and the hexagonal bore in the magnet (Figs. 2 and 3) and to encompass the end faces of the magnet and shoes and part of the outer periphery of the magnet. This metal also interlocks with the notched sides of each pole shoe 33. In this particular case, there are two diametrically opposed pole shoes 33.

The shaft 23 (Fig. 2) is extended to the left beyond the bearing 22 and has fixed thereto by a screw 36 a pinion 3'! for driving the combined timing and distributing means, as will later appear. There is a spacer ring 38 between pinion 31 and the inner race of bearing 22; a spacer ring 39 between such race and the adjacent end of the rotor; a spacer sleeve 40 between the other end of the rotor and the inner race of bearing 24; and a spacer sleeve 4| between the last-named inner race and the driven plate 42 of an impulse coupling, the driving member of which is shown at 43. Plate 4'2 is keyed to shaft 23. A nut 44, threaded on the outer end of shaft 23, holds the member 43 in axial position but permits it to turn and it also forces the member 42, the sleeve 4|, inner race of bearing 44 and sleeve 40 together and the latter against the rotor. The outer end of member 43 has lugs 43 adapted to fit into grooves in a suitable engine-driven member, indicated at h and located within the crankcase a. The impulse coupling, being well understood by those skilled in the art, has not been illustrated in detail. The coupling at starting, or at very low engine speeds, functions intermittently to impart to the rotor spring impulses. At such times, the part 43 turns intermittently relatively to member 42 to wind up the impulse spring. During normal operation, the coupling parts 42 and 43 are locked together.

The coil-carrying core l4, previously described, is held in place by two spring clips 45 (Figs. 2 and 4) one at each end of the core. Each clip is held to the frame I8 by a screw 46 (Fig. 4).

The frame l8 has fixed thereto a stud 41 (Fig. 2) for rotatably supporting the timing and distributing means to be described.

The generator, as above described, has its stator and rotor constructed and mounted in the same general manner as disclosed in the United States patent application of Ellingham and Brownlee, filed February 21, 1946, under Serial No. 649,338, now Patent 2,431,547, dated November 25, 1947, and owned by the assignee of the present application. The present generator, however, has but a single coil and omits the breaker mechanism of the last-named application, the member l8 supporting, in place of such mechanism, the timing and distributing mechamsm.

The generator described is used to supply charging current to a capacitor through a fullwave rectifier which is utilized primarily as a means for holding the charge in the capacitor and maintaining peak voltage thereon until the discharge-timing means operates to permit the discharge of the capacitor for the purpose of producing a spark. The capacitor, rectifier and discharge-timing means are all located within the cover 4.

The capacitor and rectifier are mounted in a block 48 (Figs. 2, 5, 6 and 7) of suitable insulating material and this block is held in place by three screws 49 (Fig. 1), which pass through Wall 5 of the cover and thread into the block but do not pass-through it (Figs. 6-and 7) and by" a bolt 5E] terminal post at which extends through the wall of opening 53 and carries a terminal piece ill- (see'also Fig. 7), clamped to the block by a nut 58, which also holds the capacitor in axial position inopening 53. The terminal pieces 52 and tiara electrically connected as indicated and as will later be described in detail. The other terminal of thecapacitor is connected to a wire 5% which, as shown in Fig. 6, extends part way down one side of block 253 and into and part way through a transverse groove til in the back of the block. This wire 59 (Figs. 2 and 6) is connected to a terminal piece 6i fixed by a screw 62 to one end of a metallic post 63 which is suitably fixed in and extends centrally through block it (Fig. 2), projecting beyond its front face and bearing a silver graphite brush e l.

The particular rectifier illustrated is of the selenium-cell, dry-disk type. It consists of four stacks of disks lid-mounted one stack in each of four parallel holes 5% (Fig. 2) which as shown in Fig. '10- extend transversely through block id. These four holes are spaced ninety degrees apart around a central hole and intersect the latter, whereby the disks are partially exposed to allow for dissipation of heat by way of hole to the metal walls of cover 4. A spring (355' in each hole fifiserves to hold the disks G5 in contact one with another. The ends of the holes 66 are closed by metal plates which are fixed to the sides of block 43" and serve also as connecting conductors. Thus, a horizontal kidney shaped plate 63 (Fig. 6) which is secured to a side'face of block d3 by a single centrally-located screw tit, extends across and" electrically connects one end disk or" one upper stack to the adjacent end disk of the other upper stack. Similarly, plate iii which lies below plate t8 a'nd'is held in place by a screw ii, electrically connects one end disk of one lower stack to the adjacent end diskof the other lower stack. On the opposite side of block (Fig. '1) are 'two similar but vertical plates "5?. and it held in place by screws "i i and i5, respectively. Plate 'i2 electrically connects one end disk of the right hand upper stack to the adjacent disk of the right hand lower stack. Plate '53 electrically connects one end plate of the left hand-upper stack to the adjacent end disk of the right hand lower stack; By these means the four stacks of disks are connected to form a full-wave bridge rectifier, the input terminals of which are the screw 65 and "ii and the output terminals of whichare the screws '14 and 75.

The input terminals of the rectifier are connected to coil l5. This is accomplished as set forth below. The coil has its two terminals connected one to eachof two parallel upstanding metallic spring fingers it, suitably fixed at their lower ends to the coil. The upper ends of these fingers are engaged one by the inner end of each of 'two parallel metallic pins ll. These pins are suitably fixed as by screw threading, in block 8 butdo not extend therethrough. Each carries a nut l8; whereby'to clamp against the block a terminal piece it. These pieces it are connectedby'wires Biibnetoeach of the input terblock inner end of a hole which extends through the to a wire 8 i, which extends into groovetil (Fig. 8)

and is connected to the'terminal (ii and thus to hrush E4. The output terminal '54 is connected by a wire 22 to terminal piece 52, which, asabove' described, is grounded to a walloi the metallic housing; The electrical connections are schematically shown in Fig. 14,

The discharge-timing and" distributing means will next be described. Th block 43 (Figs. 2 and 5) has on its front face a cylindrical boss 83, located coaxially with respect to brush t4 and the described stud 4'! on'member [8. An annular ring at of suitable insulating material closely fits this boss and is thereby located in proper coaxial relation with the timin'g distributing means, The rear face of ring M'abuts the front face of block nland is suitably held thereto, as will later appear. The ring 8d carries four distributor contacts 36, til, 83 and 89. short thin blade of tungsten inset into the head $6 of a rivet (Fig. 13). The heads are inset into ring 3 5 (Fig. 12) so that the outer edges of contacts lie flush with the front face of the ring.

The rivets are so set into th ring that they cannot turn so that the contacts. are radially disposed. Each rivet passes through the ring para-liel with the axis of the latter and has its rear end headed over against and thereby electrically connected to a conducting strip. As shown, the contacts 86 and til are thus connected to conducting strips 911 and 2;'respectively, while the contacts ligand 89 are thus connected to. opposit ends of a conductingstrip 93.

A central screw (Fig. '1) passes through this strip 93 and threads into ring 84 and serves to clamp to the one end of each of two conductors 95 and s5. The other end of conductor as is connected to screw and. thus to the ground. The other end of conductor 95 is connected to the ground .terminal 5'? of the capacitor. s2 and iii are set into recesses in the back of ring 83. The strips iii and 92 are bent as shown in Fig. 5 and have ends which project radially outward from the disk at diametrically opposite points and these projecting ends are respectively secured by screws 96 and 9'? to metal distributor terminals t8 and as (Fig. 2) which arefixed in Each of these terminals is set into the block 13, through thewall 5- oi cover 4 and through a boss Hill. These bosses are formed on and project outwardly from the wall 5 and have external threads to receive gland nuts Hill.

The rotating element of the timing-distributing device includes a disk Hi2 (Figs. 2, 4 and 7) of suitable insulating material which is axially slidable on a central cylindrical part Hi3 which projects from one face of a member ltd toward ring 8 5. Set into the opposite face of member lu l (Fig, 2) is a ball bearing IE5, the inner race of which telescopes over the stud 41 on member it and closely fits such. stud. The rear portion of member I M has an integral gear Hi6 which meshes with and is driven by pinion 3?. Fixed in the member ill i are two pins lil 'i (Figs. 4 and 7), paralleling its axis and extending through disk ill? for the purpose of driving the same. A

spring Hi8, encompassing. member Mid and dis-' posed between the adjacent faces of gear lilt and, disk m2, presses the disk toward the contactbearing ring 8d. A snap ring ldihheld in a groove in the outer part of stud I93, limits the move ment of disk H12 by spring H38 and retains it on Each consists of a All the strips 5H,.

the stud when the cover 4 is removed. The disk I02 has set into it three brushes H (Figs. 4 and 7) of carbon graphite arranged in angularlyspaced relation in a circular series. These brushes are pressed into engagement with a track III (Figs. 6, 7 and 12) formed on the inner face of ring 04. The disk I02 carries a contact H2 (Figs. 4 and 6), which, like the other contacts, is preferably a tungsten blade set into the head of a rivet H3, which passes through the disk and is headed over the back face of the disk. A spring I I4, which at one end is clamped between the head of rivet H3 and the front face of disk I02 (Fig, 6), extends radially (Fig. 4) inward to the center of the disk 50 that the free end of this spring is engaged by the brush 8 above described. Thus, the capacitor 55 is connected to contact H2. The brushes lie riding on track I I I maintain disk I02 so positioned that the outer edge of contact II2 lies in the same transverse plane which includes the outer edges of the contacts 86, 8'1, 88 and 89. Hence, the contact H2 will during its rotation successively engage the contacts 86, 8'1, 88 and 89 and, when this engagement occurs, the capacitor 55 will be discharged.

The discharge circuits include wires H and H6, which respectively connect the terminals 98 and 99 to one terminal of the primary windings I I1 and I I8 of two spark plug transformers, indicated diagrammatically in Fig. 14. These wires each pass through a shielding tube H9. The other terminal of each of the primary windings II! and I I8 is connected to its metallic shielding. The secondary windings I20 and I2I of the spark plug transformers each have one terminal connected to a shielding H9. The other terminals of the secondaries I28 and I2I are respectively connected to the ungrounded terminals of spark plugs I22 and I23.

Each shielding I I3 is connected to the metallic cover 4 as shown in Fig. 2, A sleeve I24, having a flange I25, is suitably fixed to the tube at one end. This sleeve fits in the hole in the end of the gland nut IOI and the latter, when screwed onto hub I08, firmly clamps flange I25 against the end face of the hub.

The wires H5 and H6 are connected to their respective terminals 98 and 99 as follows: each wire enters the open outer end of a tube I25, which is of suitable insulating material and slidably fits in the same hole that contains the terminal 98 or 99 as the case may be; the inner end of the wire is suitably fastened in the hub of a metallic disk I 21, fixed in tube I26 near the inner end of the tube; and a coil spring I28, held in the inner end of tube I25, engages at one end the disk I27 and at the other the terminal 98 or 99, as the case may be.

The shielding IE9 (Fig. 14) also serves as a conductor between the primary of each spark plug transformer and the metallic cover A to which one terminal of the capacitor 55 is connected. A complete metallic discharge circuit of good conductivity is thus provided between the primary of each transformer and capacitor 55. Each shield is furthermore made to fit, as closely as possible, its distribution wire H5 or H5, as the case may be, which it contains. The purpose here is to cancel the impedance of the distribution wires. The rimary of each transformer may, for example, have but turns and be of very low inductance. The impedance of the distribution wires would be substantial as compared to that of a primary winding unless cancelled out by the expedient hown of arranging the distribution conductor for each primary in closelyspaced relationship to its shield and so that the current flows through them in opposite directions.

A grounding switch (Figs. 2 and 8) may be conveniently provided by a spring I29, one end of which is riveted to wall 5 of cover 4 and the other end of which is adapted to be pressed into engagement with the screw 62 of the central terminal post 63 by means of a button I30, slidably mounted in said wall.

The distributor disk I02 is provided with an opening I3I (Fig. 4) therethrough. Through this opening, on may observe the intermeshing teeth of gear I06 and pinion 31. There are marks I32 and I33 provided on the gear I06 and pinion 31, respectively, which enable the proper assembly of the moving elements of the timer-distributor. When the marks I32 and I33 are in registration, the moving distributor contact H2 is in proper relation with respect to the rotor shaft 23 of the generator. The cover 4 (Fig. 11) has a window I34 in its peripheral wall 6 through which a portion of the outer peripheries of disk I02 and ring 84 may be observed. There are marks I35 and I36 on the outer peripheries of disk I02 and ring 84, respectively. When the engine is turned over so that the piston in one of its cylinders, say No. 1 cylinder, is in firing position and the marks I35 and I36 are in register, then the rotatable contact II2 will be engaged with stationary contact 85 to cause firing of that cylinder. This arrangement enables accurate timing of the ignition apparatus with the engine to be easily and conveniently effected. All that is required is to turn the shaft 23 until the marks I35 and I33 are approximately in register; turn over the engine until the piston in No 1 cylinder is in firing position; mount the magneto on the engine by applying the screw c and bolt f but not completely tightening them, and engaging the lugs 63 in the groove of engine-driven part h; then turn the housing I relative to the crankcase a until the marks I35 and I35 exactly register; and then tighten up the screw 0 and bolt 1 to clamp the housing in place.

The particular apparatus shown herein by way of illustrative example, is designed for an oddfiring two-cylinder, four cycle internal combustion engine, wherein the firing occurs at 180 degrees and 540 degree in the cycle. The generator is driven at crankshaft speed and has a two pole rotor, which produces two flux reversals per revolution, or four fiux reversals in the two revolutions making up the complete cycle of 720 degrees. Since only two sparks are desired in each such cycle at interval of 180 and 540 degrees, the sparks produced by the other flux reversals are dissipated by connecting the capacitor to ground at the intermediate positions. The timing and distributing disk I02 rotates at half the crankshaft speed and thus the firing intervals will be and 270 degrees. With the parts positioned as shown, the moving contact I I2 will, on 90 degrees movement of disk I02, engage contact 81 and the capacitor 55 will be discharged to produce a spark in one cylinder of the engine. When contact II2 moves another 90 degrees it will engage contact 88 and discharge the capacitor to ground. When this contact moves another 90 degrees, it will engage contact 89 and again discharge the capacitor to ground. A further 90 degree movement will carry contact II2 into engagement with contact 86 and discharge the capacitor to produce a spark in the other engine ':cylinder: at the. required 270 'interv'al after. the production o'f'the: first :spark and 1? l thus. complete: the cycle.

1 By omitting the conducting strip? 93 and providing other conductors, such as 9! -and'-' 92,'betweenthe contacts:88 and BQ-and terminals,such as98 and 99, foriconnection to other. distribution wires,'the* apparatuswill. be suitable fora fourcylinder. engine. 1 or 1 course,.'. the apparatus may I be designed to .serve 'engines withxany desired number of cylinders. "The generator mayhave any desired :number' of poles andAthe-Jtiming- "distributingmean any desired number-of: contacts. The one example, herein shown, will serve ;to illustrate how; the invention may. ibesprac ticed.

.The 'igeneratorflike "that TOf r the sfirstenamed "prior application, has a squarestatic fluxnwave .ipattern. :That is,- the1fiux1changes occur :quickly in short intervals and are relatively steep and,:.

between successive flux changes, are intervals of approximately constant fiux. The shape of the pole pieces I6 and the shape of the pole shoes 33 and the large angular extent of 'the pole pieces l compared to the pole shoes233of'the: rotor,.

have much to do with the formof the-static flux wave. The material, lengthand cross section of the magnet; the reluctance of the leakagepaths in the stator and rotor; and the .num-

ber of turnsin. coil. I 5 also. contribute to :the final re ult. .Eachflux. change consists ofa reversal of .flux, 'that is a. decrease in flux froma maximum in 0ne..directi0n.t0zero. and an increase flux from.zero.to .a.-maximum in theaother ,..direction.' This. occurs in the short intervalnec- 1 'essary for eachpole. shoe.33 to leave one-:pole piece l'li and connectwithlthezother .pole piece. In Fig. 3, the rotor is shownini the .:position it occupies at the end of one such reversal. A a result of this form of flux wave, the open-circuit voltage wave has a sharply rising portion, an immediately-ensuing and sharply falling portion, followed by a portion where there i substantially no change in voltage. The flux curve and voltage curve for no-load operation are modified when the generator is under load. The design of the magnetic circuit is such that the amount of magnetomotive force acting through the coil core !4 is limited. When the speed increases, the generated counter magnetomotive force reaches this limit and there can be no further increase in current with increase in speed. When current flows, a counter magnetomotive force is produced which limits the rate of change of the fiux. The completion of the flux reversal and the peak of the resulting voltage on the capacitor will occur later and later as the speed of the generator increases. But so far as speed is concerned, the flux rate is substantially constant over the normal speed range of the generator and so is the resulting voltage on the capacitor. The rectifier, by its valve-like action prevents back flow of current and maintains the voltage or the capacitor at peak value until the timing-distributing means acts to couple the capacitor to a discharge circuit. Then the capacitor, which was charged over a substantial period of movement of the rotor, is discharged instantaneously and a heavy flow of current at high frequency occurs for an instant in the primary of a spark plug transformer to cause the production of an ignition spark. The operation is essentially the same in all particulars as set forth in the first-named prior application.

It is to be noted that the assembly of all the quency type.

the wires are put in place.

the member-48 is placed in cover '4 and the screws 49 applied to fasten it in place. The bolt-50 is .then'applied; the terminal 52 placed'on the protruding end of the bolt; and the nut 5i screwed onto the bolt and-turned upto clamp the terminal against the block '48.

The invention provides a compact arrangement of parts within asingle casing section 4, which, when attached to an electrical generator having suitable characteristics, will complete an ignition apparatu of the low-tension, high-fre- No electrical connections need to be made, except-the connection of the several distribution wiresfrom the terminals on cover 4 tothe spark-plug transformers. The supply current connections are automatically made during the act of applying the cover 4 to casing l,

when the pins" engage the-springs 16 of coil l5. All that isnecessary is to mount the distributor. rotor .onits studfl. on the rotor-shaftbearing supporting frame .18. The gear I06 is turned until it is so meshed with piniont'l that .theimarks I32 andl33 coincide. Then; thecover .is put in place and. fastened by the screws 8.

A magneto, such .-as disclosed in'zthe second- .namedxapplication, may. be used as the. generator for charging the'capacitor by providing a slightly diiferent frame, lacking the breaker mechanism and having the distributor support and driving pinion therefor and by substituting for the primary and secondary coils, a single coil such as l5. A breakerless magneto is thus provided and the timing of the sparks is effected solely by the rotating distributor contact H2.

The invention thus provides improved ignition apparatus for use in ignition systems of the lowtension, high-frequency type wherein the ignition sparks are produced by the discharge of a capacitor and are timed solely by the rotatable member of the distributor.

We claim:

1. Ignition apparatus, comprising, a casing having a wall embordered by an endless marginal flange and adapted for connection to the housing of an electrical generator, a member of insulating material having one side face abutting said wall and fixed thereto and encompassed by said flange, a distributor ring carryin contacts fixed to the opposite face of said member, a distributor brush mounted centrally of said ring, a capacitor and a rectifier mounted in said member, terminals fixed to said member and projecting therefrom for connection to said generator, electrical connections from said terminals to the input terminals of the rectifier and from the output terminals of the rectifier to the capacitor, an electrical connection from one terminal of the capacitor to said brush and from the other 'terminal thereof to said casing, terminals on said member adapted for connection outside the casing to distribution wires and connected inside the casing one to each contact on said ring, and a rotatable distributor element having a contact to successively engage the first-named contacts 11 and a conductor connected to the last-named contact and engaged with said brush.

2. Ignition apparatus, comprising, a member of insulating material having front and back faces and connecting side and end faces, a distributor brush mounted in the member and projecting through its front face, a series of distributor contacts surrounding the brush, openings extending from one side face into said member above and below the brush, a capacitor in one opening, a rectifier in the other opening, supply terminals fixed to the front face of said member, electrical connections from the supply terminals to the input terminals of the rectifier and from the output terminals of the latter to the capacitor and from the capacitor one to said brush and one to be connected to the ground, discharge circuit terminals on said member and connected one to each said contact and having sockets opening to the back face of said member, a casing having a wall embordered by a marginal flange, said member With the parts mounted therein and with said electrical connections made adapted to be inserted in said casing with its back face against said wall and its side and end faces encompassed by said flange, and means securing said member to said wall, said wall having openings therethrough connecting one with each of said sockets.

3. Ignition apparatus, comprising, a member of insulating material having front and back faces and connecting side and end faces, a distributor brush mounted in the member and projecting through its front face, a series of distributor contacts surrounding the brush openings extending from one side face into said member above and below the brush, a, capacitor in one opening, a rectifier in the other opening, supply 12 terminals fixed to the front face of said member, electrical connections from the supply terminals to the input terminals of the rectifier and from the output terminals of the latter to the capacitor and from the capacitor one to said brush and one to be connected to the ground, discharge circuit terminals on said member and connected one to each said contact andhaving sockets opening to the back face of said member, a casing having a wall embordered by a marginal flange, said member with the parts mounted therein and with said electrical connections made adapted to be inserted in said casing with its back face against said wall and its side and end faces encompassed by said flange, means for fastening said member to said wall, and means for connecting said ground connection of the capacitor to said wall, said wall having openings therethrough connecting one with each of said sockets.

SIDNEY K. SMART. ALLEN L. BROWNLEE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,058,456 Murphy Apr. 8, 1913 1,935,127 Nowosielski Oct. 14, 1933 2,074,545 Harmon Mar. 23, 1937 2,104,140 Spengler Jan. 4, 1938 2,184,315 Peters Dec. 26, 1939 2,240,804 Schwartzman May 6, 1941 2,258,665 Vogel Oct. 14, 1941 2,291,652 Rose Aug. 4, 1942 2,352,894 Harmon July 4, 1944 

